dm cache: add policy name to status output

The cache's policy may have been established using the "default" alias,
which is currently the "mq" policy but the default policy may change in
the future.  It is useful to know exactly which policy is being used.

Add a 'real' member to the dm_cache_policy_type structure and have the
"default" dm_cache_policy_type point to the real "mq"
dm_cache_policy_type.  Update dm_cache_policy_get_name() to check if
real is set, if so report the name of the real policy (not the alias).

Requested-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer
2014-01-15 21:06:55 -05:00
parent 74aa45c33c
commit 2e68c4e6ca
5 changed files with 17 additions and 3 deletions

View File

@@ -2832,7 +2832,7 @@ static void cache_resume(struct dm_target *ti)
* <#demotions> <#promotions> <#dirty>
* <#features> <features>*
* <#core args> <core args>
* <#policy args> <policy args>*
* <policy name> <#policy args> <policy args>*
*/
static void cache_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
@@ -2900,6 +2900,8 @@ static void cache_status(struct dm_target *ti, status_type_t type,
}
DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
if (sz < maxlen) {
r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
if (r)